• Journal of the Korea Academia-Industrial cooperation Society
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• 제22권2호
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• pp.593-601
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• 2021

The axial fan is an element of a blower used for ventilation in various industrial fields. Many studies on aerodynamic performance have been conducted to assess axial fans using fluid dynamics. The subject was a large axial fan size, 1800 mm in diameter with 100 horsepower. The blower's axial fan consisted of blades, hubs, hub caps, and bosses are important components. The blade design has a great influence on the aerodynamic performance. 3D point data is extracted using an aerodynamic performance prediction program, and a 3D modeling shape is generated. The blades and hubs, which are important components, can be easily modified if processed by cutting owing to the environment in which blades and hubs are manufactured through die casting or gravity casting. In this study, the structural safety of components and the analysis results of weak areas at the rated operating speed of the axial fan were verified using the maximum stress and safety factor. The tip clearance reflected in the design was the rotation of the blade. To check whether there is interference with other components, the displacement result was derived to verify the structural safety of the axial fan.

• Clean Technology
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• 제28권4호
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• pp.323-330
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• 2022

Microfluidic paper-based analytical devices (μPADs) have recently been in the spotlight for their applicability in point-of-care diagnostics and environmental material detection. This study presents a double-sided printing method for fabricating 3D-μPADs, providing simple and cost effective metal ion detection. The design of the 3D-μPAD was made into an acryl stamp by laser cutting and then coating it with a thin layer of PDMS using the spin-coating method. This fabricated stamp was used to form the 3D structure of the hydrophobic barrier through a double-sided contact printing method. The fabrication of the 3D hydrophobic barrier within a single sheet was optimized by controlling the spin-coating rate, reagent ratio and contacting time. The optimal conditions were found by analyzing the area change of the PDMS hydrophobic barrier and hydrophilic channel using ink with chromatography paper. Using the fabricated 3D-μPAD under optimized conditions, Ni²⁺, Cu²⁺, Hg²⁺, and pH were detected at different concentrations and displayed with color intensity in grayscale for quantitative analysis using ImageJ. This study demonstrated that a 3D-μPAD biosensor can be applied to detect metal ions without special analysis equipment. This 3D-μPAD provides a highly portable and rapid on-site monitoring platform for detecting multiple heavy metal ions with extremely high repeatability, which is useful for resource-limited areas and developing countries.

• Journal of the Korean Society of Marine Environment & Safety
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• 제29권6호
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• pp.536-542
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• 2023

Satellites represent cutting-edge technology, of ering significant advantages in spatial and temporal observations. National agencies worldwide harness satellite data to respond to marine accidents and analyze ocean fluctuations effectively. However, challenges arise with high-resolution satellite-based sea surface temperature data (Operational Sea Surface Temperature and Sea Ice Analysis, OSTIA), where gaps or empty areas may occur due to satellite instrumentation, geographical errors, and cloud cover. These issues can take several hours to rectify. This study addressed the issue of missing OSTIA data by employing LaMa, the latest deep learning-based algorithm. We evaluated its performance by comparing it to three existing image processing techniques. The results of this evaluation, using the coefficient of determination (R²) and mean absolute error (MAE) values, demonstrated the superior performance of the LaMa algorithm. It consistently achieved R² values of 0.9 or higher and kept MAE values under 0.5 ℃ or less. This outperformed the traditional methods, including bilinear interpolation, bicubic interpolation, and DeepFill v1 techniques. We plan to evaluate the feasibility of integrating the LaMa technique into an operational satellite data provision system.

• The Journal of the Convergence on Culture Technology
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• 제9권5호
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• pp.597-603
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• 2023

The paradigm of military operations has evolved from platform-centric warfare to network-centric warfare and further to information-centric warfare, driven by advancements in information technology. In recent years, with the development of cutting-edge technologies such as big data, artificial intelligence, and the Internet of Things (IoT), military operations are transitioning towards knowledge-centric warfare (KCW), based on artificial intelligence. Consequently, the military places significant emphasis on integrating advanced information and communication technologies (ICT) to establish reliable C4I (Command, Control, Communication, Computer, Intelligence) systems. This research emphasizes the need to apply data mining techniques to analyze and evaluate various aspects of C4I systems, including enhancing combat capabilities, optimizing utilization in network-based environments, efficiently distributing information flow, facilitating smooth communication, and effectively implementing knowledge sharing. Data mining serves as a fundamental technology in modern big data analysis, and this study utilizes it to analyze real-world cases and propose practical strategies to maximize the efficiency of military command and control systems. The research outcomes are expected to provide valuable insights into the performance of C4I systems and reinforce knowledge-centric warfare in contemporary military operations.

• Journal of Korean Tunnelling and Underground Space Association
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• 제26권1호
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• pp.39-58
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• 2024

Tunnel Boring Machines (TBM) use multiple disc cutters to excavate tunnels through rock. These cutters wear out due to continuous contact and friction with the rock, leading to decreased cutting efficiency and reduced excavation performance. The rock's abrasivity significantly affects cutter wear, with highly abrasive rocks causing more wear and reducing the cutter's lifespan. The Cerchar Abrasivity Index (CAI) is a key indicator for assessing rock abrasivity, essential for predicting disc cutter life and performance. This study aims to develop a new method for effectively estimating CAI using rock strength, petrological characteristics, linear regression, and machine learning. A database including CAI, uniaxial compressive strength, Brazilian tensile strength, and equivalent quartz content was created, with additional derived variables. Variables for multiple linear regression were selected considering statistical significance and multicollinearity, while machine learning model inputs were chosen based on variable importance. Among the machine learning prediction models, the Gradient Boosting model showed the highest predictive performance. Finally, the predictive performance of the multiple linear regression analysis and the Gradient Boosting model derived in this study were compared with the CAI prediction models of previous studies to validate the results of this research.

• Journal of Environmental Policy
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• 제6권1호
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• pp.41-60
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• 2007

Attempts were made to define the elements of debates, impact of decisions of the Access to Genetic Resources and Benefit-sharing(ABS) of the Conference of the Parties(COP) to the Convention on Biological Diversity(CBD) In Korea. Providing policy suggestions to cope with ABS, a cross-cutting issue of the meetings of the COP, was also undertaken. Meetings concerning ABS deal with several key matters such as an international regime, which is a legally binding implementation tool of the Bonn Guidelines, an international certificate of genetic resources' origin/source/legal provenance, and disclosure of origin of genetic resources, compliance measures with prior informed consent of the Contracting Parties providing such resources and with mutually agreed terms on which access was granted. Developing countries, rich in biodiversity and genetic resources, use the CBD as a major tool to maximize their national profits. They demand for national sovereign rights for the genetic resources and indigenous communities providing associated traditional knowledge. At the meetings of the COP, in addition, they requested that developed countries should transfer technologies and provide a financial mechanism for resource conservation to them. On the contrary, the developed countries argue that facilitating access to genetic resources is essential for scientific research and development, and that both Intellectual Property Rights and biotechnology using genetic resources should be protected to maximize their national benefits. Decisions of the COP concerning the Bonn Guidelines and compliance measures with ABS will affect on various socioeconomic fields of Korea, a country which is short of genetic resources. Especially, the importation of genetic resources and land development which might damage genetic resources will be limited seriously. Consequently, overall expenses will increase for the securing genetic resources from the foreign countries and developing biotechnology for conservation and sustainable uses of genetic resources. To minimize the adverse impacts, we endeavor to establish our clear standpoint and to lead the international trends, which are favorable for us. In order to achieve these objectives, government needs i) to proceed researches to lead the international ABS debates actively and to prepare the expected decisions of the future meetings of the COP, ii) to establish a national implementation plan to cope with the ABS and its related decisions, iii) to examine and improve the efficiencies of the national implementation plan with a proper monitoring system, and iv) cope with the other international meetings including the meetings of Trade Related Intellectual Properly Rights and International Treaty on Plant Genetic Resources for Food and Agriculture actively.

• Journal of Korean Ophthalmic Optics Society
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• 제18권3호
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• pp.231-239
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• 2013

Purpose: To design and fabricate the auto pattern maker for the development. Methods: we got the necessary data, needed in design, by using CAD. Based on the these data, we fabricated the trial product for the development of the auto pattern maker. Results: The auto pattern maker were composed with combinations of many elements; pattern making assembly, control panel, frame attachment and prober unit. The pattern making assembly was comprised of the cutter, the pattern holder, pattern remover and silence cover which could minimize the sound during the cutting process. The control panel was designed to be connected and operated with the main printed circuit board. The prober could get the eye shape data by scanning of 1.8 degrees around the groove of the frame through the encoding data according to the address. After starting, scanning was carried out in two passes, i.e. one right-handed and one left-handed. Communication connector could send the eye shape data from auto pattern maker to outer system with the RS232C transmission system. By using the one-way analysis of variance, we got the error rate of cut pattern size for ${\Phi}22mm$, ${\Phi}55mm$ and ${\Phi}62mm$. Because F-value was 0.510 and p-value was 0.601, no statistically significant differences were found. Also, the mean cutting error of the auto pattern maker was 0.0274 mm. Conclusions: we could succeed in making the trial product by applying it to the development of the auto pattern maker. The role of this auto pattern maker is to find a exact required size of lens to fit the frame by measuring the frame. The acquired data are transferred to outer system for grinding and finishing with patternless process. Also, the trial product can produce pattern to fit the frame. Therefore, it was confidently expected that the optometrists could handily produce pattern to fit the frame with this trial product and dispense the ophthalmic lens because of its efficiency and convenience compared to the past.

• Journal of Korean Society of Forest Science
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• 제4권1호
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• pp.1-8
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• 1965

In this study, the present institution of reserved forests in Korea has been criticized through the analysis of the present situation of reserved forests in Korea, and mainly, on designation and cancellation of them because of this important institution thought as restriction of forest ownership. Reserved forest land in Korea as of the end of 1962 is 996,915 chungbo in area, or about 14.8% of the total forest land area, 6,750,324 chungbo in Korea, and we can find that the area of reserved forest land has increased remarkably since the Liberation in 1945, in comparison with about 180,000 chungbo-a little over 1% of the total forest land area, 16,000,000 chungbo, through Southern and Northern Korea till the Liberation in 1945. This fact clearly proves that Korean forests are extremely devastated since the Liberation in 1945, and in Korea we can find that reserved forest policy is very important in forest policy, consequently, reserved forest institution must be dealt with care. Moreover, the area of reserved forest land, 996,915 chungbo, which is divided into 43,820 chungbo of national forest land, 59,302 chungbo of public forest land, 893,793 chungbo of private forest land, and private forest land is excellently large, or about 89.7% of the total area of reserved forest land. In this number, we may understand the fact that reserved forests have the most influences on private forests, therefore, we may recognize that it is necessary for reserved forest constitution which is infringement of private right to be carried out carefully. From the first beginning, the institution of reserved forests is serious restriction to the forest ownership. Consequently, when the area of reserved forest land grows, it interferes seriously with the free forest management and the desire for forest own ership is decreased, at the same time, forest enterprise results in obstruction. Especially, Korean forests are destroyed extremely at present, so, intensification of reserved forest institution is unavoidable for completion of the national aim which forests have, but the author thinks that reserved forest institution must be as avoidable as possible, and we have to obtain good results by supervision of forest management which is regulated in the Forest Law. Consequently, designation of reserved forests must be minimized, and although forests were already designated as reserved forests they must be cancellated as fast as fast as possible and put them free in the owner's hands when they are in cancellation conditions. According to the provision of Article 18 of the Forest Law concrete cases designated as a reserved forest are enumerated for the purpose of maintaining the forest ownership and avoiding to give the forest authorities a free hand in order to protect forest owners from one-sided damage. Therefore, the forest authorities must not abuse the institution of reserved forests, and it is not good tendency to give only the authorities a free hand in eesignation and cancellation of reserved forests, and especially, when the forest owners object to that, establishing some legal organization like the reserved forest council in each province in order to hear about impartial opinions, and it is more suitable than administrative disposal by the same organization. The compensation of damages for reserved forests by the provision of Article 25 of the Forest Law is a different problem by forest policy, but the results of compensation of damages regulated in the Forest Law are wholly lacking up to now, the author thinks that this is caused to poor forest cover, the forest owner's unconcern and insincerity of administrative authorities. Therefore, the government must enlarge the range of compensation and minimize the forest owner's economic sacrifice, also, the government must mollify the conditions of the legal restrictions to reserved forests, and harmonize with functions of national conservation and economy. This means that it is necessary to modify the restrictive conditions for the effective utilization of forest resources within the range in which can be attained the purpose of designation, from permanent prohibition of cutting. Except the reserved forests of fish habitat, public sanitation, maintaining scenery and navigational mark ect., most of reserved forests are prohibited from cutting, and the present situation of forests in Korea are extremely devastated and those forests are not so expected in cancellation possibility in near future. Therefore, when the forest owners apply for national purchase of those reserved forests, the government had better nationalize them, protect and manage to reduce the forest owner's economic sacrifice.

• KOMUNHWA
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• 제70호
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• pp.63-88
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• 2007

The purpose of this writing is to examine the places and instruments of the dissection for deformed animal carcasses excavated in shellfish stacks of the period of the Proto-Three Kingdoms(삼한) and the Three Kingdoms(삼국). The remains were chosen, which had been excavated and finished in the analysis of the animal carcasses, and the main objects are all shells and deer, especially among Mammalia. As the result, the dissection of shells was not taken place in the habitats of the animals, but inside or around of the residence of the people. For deer, too, it was done in the public place or specific area around and inside the residence. As concerns the method of dissection for shells, for Pelecypoda(부족류), represented by Meretrix lusoria(백합), the inner meat was taken out by wrenching the shell with a kind of small knives, or by boiling, and sometimes by cracking the middle of the shell in the case of big Meretrix lusoria and Dosinorbis japonicus(떡조개). For Rapana venosa(피뿔고둥), representative of Gastropoad(배발류), the people broke the top or some parts of the body to get the inner meat or used some kind of needles and stylus to pick the inner meat out after boiling. Abalones‘ meat was attached firmly to the shell, so very sharp and proper metal instruments were used to take the meat out Relatively small-sized Reishia clavigera(대수리),Top shell(밤고둥) meats were taken out by breaking the top parts after boiling, then sucking the meats, or by picking them out by using needles and stylus in the original shape. In the case of large Mammalia like deer, in the full consideration of the point that deer itself are used in various ways, they were dissected in the order of skinning, taking out the internal organs, cutting front and rear legs, separating joint parts and meats, extracting bone-marrow by 철정, 철부, ironed hand knife in very delicate ways. It seems that skinning, and front and rear legs' cutting were taken place in the place around the residence, on the other hand joint parts' separating and bone-marrow extracting in the residence. The tools for the dissection were confirmed to be hand-knife, honed ax, hammer stone, bondstone, needles and stylus, and some other sharp instrument. They were used properly according to objects.

• Food Science and Preservation
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• 제24권6호
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• pp.746-757
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• 2017

This study was performed to evaluate the effect of different freezing conditions and storage periods on physicochemical and microbial characteristics of garlic. Garlics were washed, dried, sliced to 0.3 cm then packed in LDPE+LLDPE film bags. They were treated with still-air freezing at $-20^{\circ}C$ (SAF20), $-40^{\circ}C$ (SAF40) and immersed-liquid freezing at $-40^{\circ}C$ (ILF40). Frozen garlics were stored under frozen storage conditions for 7 months at $-20^{\circ}C$ and quality characteristics were measured monthly during the frozen storage. Freezing rate of garlic was the fastest in ILF 40 (10 min), SAF40 (40 min) and SAF20 (1,600 min) sequentially. In ILF40, drip loss, cutting force, total aerobic bacteria count and pH were the lowest, whereas pyruvic acid and allicin content were the highest (p<0.05) during frozen storage, these results were the most similar characteristics with the fresh garlic. During frozen storage, drip loss, color difference and total organic acid content were significantly fluctuated in SAF20 (p<0.05), while they were not changed in ILF40. Overall, total aerobic bacteria count and pH decreased, cutting force, pyruvic acid and allicin content remained unchanged in all groups. In conclusion, the optimal freezing conditions for garlic with the least quality changes was considered to be ILF40 (immersed liquid freezing), keeping quality characteristics up to 7 months by freezing storage.